This is a family of nonvenomous snakes found in America, Africa, Europe, Asia, and some Pacific Islands. Relatively primitive snakes, adults are medium to large in size, with females usually larger than the males.

These are native to Mauritius and a few islands around it, especially Round Island. They also used to be found on the island of Mauritius, but were extirpated there due to human influence and foraging pigs in particular.

These are a family of venomous snakes found in tropical and subtropical regions around the world, terrestrially in Asia, Australia, Africa, North America, and South America, and aquatically in the Pacific and Indian Oceans.

These are a family of nonvenomous snakes found from Mexico and the West Indies south to southeastern Brazil. These are small to medium-sized fossorial snakes, some with beautiful and striking color patterns.

These are a family of venomous snakes found in most parts of the world, excluding Antarctica, Australia, New Zealand, Madagascar, Hawaii, various other isolated islands, and north of the Arctic Circle. All have relatively long, hinged fangs that permit deep penetration and injection of venom.

They are found mostly in the tropical regions of Africa, Asia, the Americas, and all mainland Australia and various islands. They live underground in burrows, and since they have no use for vision, their eyes are mostly vestigial. They have light-detecting black eye spots, and teeth occur in the upper jaw. The tail ends with a horn-like scale.